/*
 * Copyright (C) 2008 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */

package com.google.common.collect;

import static com.google.common.base.Preconditions.checkNotNull;

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import com.google.j2objc.annotations.Weak;
import java.io.Serializable;
import java.util.Map.Entry;
import java.util.Spliterator;
import java.util.Spliterators;
import java.util.function.Consumer;
import javax.annotation.Nullable;

/**
 * {@code entrySet()} implementation for {@link ImmutableMap}.
 *
 * @author Jesse Wilson
 * @author Kevin Bourrillion
 */
@GwtCompatible(emulated = true)
abstract class ImmutableMapEntrySet<K, V> extends ImmutableSet<Entry<K, V>> {
    static final class RegularEntrySet<K, V> extends ImmutableMapEntrySet<K, V> {
        @Weak
        private final transient ImmutableMap<K, V> map;
        private final transient Entry<K, V>[] entries;

        RegularEntrySet(ImmutableMap<K, V> map, Entry<K, V>[] entries) {
            this.map = map;
            this.entries = entries;
        }

        @Override
        ImmutableMap<K, V> map() {
            return map;
        }

        @Override
        public UnmodifiableIterator<Entry<K, V>> iterator() {
            return Iterators.forArray(entries);
        }

        @Override
        public Spliterator<Entry<K, V>> spliterator() {
            return Spliterators.spliterator(entries, ImmutableSet.SPLITERATOR_CHARACTERISTICS);
        }

        @Override
        public void forEach(Consumer<? super Entry<K, V>> action) {
            checkNotNull(action);
            for (Entry<K, V> entry : entries) {
                action.accept(entry);
            }
        }

        @Override
        ImmutableList<Entry<K, V>> createAsList() {
            return new RegularImmutableAsList<Entry<K, V>>(this, entries);
        }
    }

    ImmutableMapEntrySet() {}

    abstract ImmutableMap<K, V> map();

    @Override
    public int size() {
        return map().size();
    }

    @Override
    public boolean contains(@Nullable Object object) {
        if (object instanceof Entry) {
            Entry<?, ?> entry = (Entry<?, ?>) object;
            V value = map().get(entry.getKey());
            return value != null && value.equals(entry.getValue());
        }
        return false;
    }

    @Override
    boolean isPartialView() {
        return map().isPartialView();
    }

    @Override
    @GwtIncompatible // not used in GWT
    boolean isHashCodeFast() {
        return map().isHashCodeFast();
    }

    @Override
    public int hashCode() {
        return map().hashCode();
    }

    @GwtIncompatible // serialization
    @Override
    Object writeReplace() {
        return new EntrySetSerializedForm<K, V>(map());
    }

    @GwtIncompatible // serialization
    private static class EntrySetSerializedForm<K, V> implements Serializable {
        final ImmutableMap<K, V> map;

        EntrySetSerializedForm(ImmutableMap<K, V> map) {
            this.map = map;
        }

        Object readResolve() {
            return map.entrySet();
        }

        private static final long serialVersionUID = 0;
    }
}
